it's a "vacation" in the sense that you literally don't have to do anything all day but stay alert (which people should be doing anyway)...the short time is a test of endurance because, if you get into a fight, you will probably be there longer than one day...quite the mental stimulation.

there is also getting to see the human misery up close...poor bastards that might never be getting out...no actor can ever capture that sort of pathos, it can only be seen in person.